CN108715016B

CN108715016B - Injection molding machine

Info

Publication number: CN108715016B
Application number: CN201810269897.6A
Authority: CN
Inventors: 森田洋; 堀田大吾
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2017-03-31
Filing date: 2018-03-29
Publication date: 2020-08-14
Anticipated expiration: 2038-03-29
Also published as: EP3381640B1; CN108715016A; JP6840600B2; EP3381640A1; JP2018171812A

Abstract

The invention provides an injection molding machine capable of inhibiting damage of a frame supporting a movable component. The injection molding machine of the invention comprises: a frame; a movable member supported by the frame; a movement control unit that controls movement of the movable member relative to the frame; and a frame deformation evaluation unit that performs at least one of measurement and estimation of deformation of the frame caused by movement of the movable member.

Description

Injection molding machine

Technical Field

The present application claims priority based on japanese patent application No. 2017-072292, applied on 3/31/2017. The entire contents of this Japanese application are incorporated by reference into this specification.

The present invention relates to an injection molding machine.

Background

The injection molding machine of patent document 1 describes the following: when an acceleration sensor is provided on a fixed disk to which a fixed mold is attached, acceleration of vibration of the fixed disk detected by the acceleration sensor is input to a controller that controls a toggle mechanism, and a cross head is driven to clamp a movable mold against the fixed mold, the vibration of the fixed disk is monitored between an open mold position where the movable mold is opened only by a predetermined opening modulus and a mold closing position where the movable mold is in contact with the fixed mold, and when vibration exceeding a predetermined threshold value is detected, the cross head is stopped and the mold closing operation is stopped, whereby, when foreign matter is trapped in the mold, the foreign matter can be reliably detected and the mold closing operation can be stopped. The reason why the acceleration sensor is provided on the stationary platen is as follows: the stationary platen is not a movable member and therefore is not affected by acceleration due to movement of the member.

Patent document 1: japanese patent laid-open publication No. 2010-247410

The injection molding machine has a frame for supporting a movable member such as a movable platen to which a movable mold is attached. When the movable member is moved relative to the frame, the frame is deformed by a reaction force received from the movable member. Since the movement of the movable member is repeated, the deformation is repeated, and the frame may be damaged.

Disclosure of Invention

The present invention has been made in view of the above problems, and a main object thereof is to provide an injection molding machine capable of suppressing damage to a frame supporting a movable member.

In order to solve the above problem, according to an aspect of the present invention, there is provided an injection molding machine including:

a frame;

a movable member supported by the frame;

a movement control unit that controls movement of the movable member relative to the frame; and

and a frame deformation evaluation unit that performs at least one of measurement and estimation of deformation of the frame caused by movement of the movable member.

Effects of the invention

According to an aspect of the present invention, there is provided an injection molding machine capable of suppressing damage to a frame supporting a movable member.

Drawings

Fig. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment.

Fig. 2 is a diagram showing a state of the injection molding machine according to an embodiment when clamping a mold.

Fig. 3 is a diagram showing a mold clamping device and a frame according to an embodiment.

Fig. 4 is a diagram showing constituent elements of a control device according to an embodiment as functional blocks.

Fig. 5 is a diagram showing a control device for limiting the magnitude of torque by the movement correction unit according to an embodiment.

Fig. 6 is a diagram showing a control device for correcting a velocity pattern by a movement correction unit according to an embodiment.

Fig. 7 is a diagram showing a speed pattern of the crosshead before correction, deformation of the frame before correction, a speed pattern of the crosshead after correction, and deformation of the frame after correction in the mold closing process and the mold clamping process according to the embodiment.

In the figure: 100-mold clamping apparatus, 110-fixed platen, 120-movable platen, 160-mold clamping motor, 161-mold clamping motor encoder, 162-mold clamping motor torque detector, 700-control apparatus, 711-movement control section, 712-control command calculation section, 713-drive section, 715-frame deformation evaluation section, 716-movement correction section, 900-frame, 901-upper frame-shaped section, 902-lower frame-shaped section, 903-pillar section, 904-weld section, 905-frame deformation detector weld section.

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings, but the same or corresponding components are denoted by the same or corresponding reference numerals in the drawings, and the description thereof will be omitted.

(injection molding machine)

Fig. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment. Fig. 2 is a diagram showing a state of the injection molding machine according to an embodiment when clamping a mold. In fig. 1 to 2, the X direction, the Y direction, and the Z direction are perpendicular to each other. The X direction and the Y direction indicate horizontal directions, and the Z direction indicates a vertical direction. When the mold clamping device 100 is horizontal, the X direction is the mold opening and closing direction, and the Y direction is the width direction of the injection molding machine.

The injection molding machine includes a mold clamping device 100, an ejector 200, an injection device 300, a moving device 400, a control device 700, and a frame 900. Hereinafter, each constituent element of the injection molding machine will be described.

(mold clamping device)

In the description of the mold clamping apparatus 100, the moving direction of the movable platen 120 when the mold is closed (the right direction in fig. 1 and 2) is set to the front, and the moving direction of the movable platen 120 when the mold is opened (the left direction in fig. 1 and 2) is set to the rear.

The mold clamping device 100 closes, clamps, and opens the mold of the mold device 10. The mold clamping device 100 is, for example, horizontal, and the mold opening/closing direction is horizontal. The mold clamping device 100 includes a fixed platen 110, a movable platen 120, a toggle base 130, a connecting rod 140, a toggle mechanism 150, a mold clamping motor 160, a motion conversion mechanism 170, and a mold thickness adjustment mechanism 180.

The stationary platen 110 is fixed relative to the frame 900. The fixed mold 11 is attached to a surface of the fixed platen 110 facing the movable platen 120.

The movable platen 120 is movable in the mold opening/closing direction with respect to the frame 900. A guide 101 for guiding the movable platen 120 is laid on the frame 900. The movable mold 12 is attached to a surface of the movable platen 120 facing the fixed platen 110.

The movable platen 120 is moved forward and backward with respect to the fixed platen 110 to perform mold closing, mold clamping, and mold opening. The fixed mold 11 and the movable mold 12 constitute a mold apparatus 10.

The toggle base 130 is connected to the fixed platen 110 with a gap therebetween, and is mounted on the frame 900 so as to be movable in the mold opening/closing direction. The toggle seat 130 may be movable along a guide laid on the frame 900. The guide of the toggle seat 130 may be common with the guide 101 of the movable platen 120.

In the present embodiment, the fixed platen 110 is fixed to the frame 900, and the toggle seat 130 is movable in the mold opening and closing direction with respect to the frame 900, but the toggle seat 130 may be fixed to the frame 900, and the fixed platen 110 may be movable in the mold opening and closing direction with respect to the frame 900.

The connecting rod 140 connects the fixed platen 110 and the toggle seat 130 with a gap L therebetween in the mold opening and closing direction. A plurality of (e.g., 4) connecting rods 140 may be used. Each tie bar 140 is parallel to the mold opening and closing direction and extends according to the mold clamping force. At least one of the tie bars 140 is provided with a tie bar deformation detector 141 that detects deformation of the tie bar 140. The connecting rod deformation detector 141 transmits a signal indicating the detection result to the control device 700. The detection result of the tie bar deformation detector 141 is used for detection of the mold clamping force and the like.

In the present embodiment, the tie bar deformation detector 141 is used as the mold clamping force detector for detecting the mold clamping force, but the present invention is not limited to this. The mold clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like, and the attachment position thereof is not limited to the tie bar 140.

The toggle mechanism 150 is disposed between the movable platen 120 and the toggle base 130, and moves the movable platen 120 in the mold opening/closing direction with respect to the toggle base 130. The toggle mechanism 150 is constituted by a cross 151, a pair of links, and the like. Each link group includes a 1 st link 152 and a 2 nd link 153 telescopically coupled by a pin or the like. The 1 st link 152 is pivotally attached to the movable platen 120 by a pin or the like, and the 2 nd link 153 is pivotally attached to the toggle seat 130 by a pin or the like. The 2 nd link 153 is attached to the crosshead 151 via the 3 rd link 154. When the crosshead 151 moves forward and backward with respect to the toggle seat 130, the 1 st link 152 and the 2 nd link 153 extend and contract, and the movable platen 120 moves forward and backward with respect to the toggle seat 130.

The structure of the toggle mechanism 150 is not limited to the structure shown in fig. 1 and 2. For example, in fig. 1 and 2, the number of fulcrums of each link group is 5, but may be 4, and one end of the 3 rd link 154 may be coupled to the fulcrums of the 1 st link 152 and the 2 nd link 153.

The mold clamping motor 160 is attached to the toggle base 130 to operate the toggle mechanism 150. The mold clamping motor 160 moves the crosshead 151 forward and backward with respect to the toggle base 130, thereby extending and contracting the 1 st link 152 and the 2 nd link 153 and moving the movable platen 120 forward and backward with respect to the toggle base 130. The mold clamping motor 160 is directly coupled to the motion conversion mechanism 170, but may be coupled to the motion conversion mechanism 170 via a belt, a pulley, or the like.

The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft 171 and a screw nut 172 screwed to the screw shaft 171. Balls or rollers may be interposed between the screw shaft 171 and the screw nut 172.

The mold clamping device 100 performs a mold closing process, a mold clamping process, a mold opening process, and the like under the control of the control device 700.

In the mold closing step, the movable platen 120 is moved forward and the movable mold 12 is brought into contact with the fixed mold 11 by driving the mold clamping motor 160 to move the crosshead 151 to the mold closing end position at a set speed. The position and speed of the crosshead 151 are detected using, for example, a mold clamping motor encoder 161 and the like. The clamp motor encoder 161 detects the rotation of the clamp motor 160, and transmits a signal indicating the detection result to the control device 700.

In the mold clamping process, the mold clamping motor 160 is further driven to move the crosshead 151 further from the mold closing end position to the mold clamping position, thereby generating a mold clamping force. During mold clamping, a cavity space 14 is formed between the movable mold 12 and the fixed mold 11, and the injection device 300 fills the cavity space 14 with a liquid molding material. The filled molding material is cured to obtain a molded article. The number of the cavity spaces 14 may be plural, and in this case, plural molded articles can be obtained at the same time.

In the mold opening step, the mold closing motor 160 is driven to retract the crosshead 151 to the mold opening completion position at a set speed, thereby retracting the movable platen 120 and separating the movable mold 12 from the fixed mold 11. After that, the ejector 200 ejects the molded product from the film 12.

The setting conditions in the mold closing step and the mold clamping step are set comprehensively as a series of setting conditions. For example, the speed and position of the crosshead 151 (including the speed switching position, the mold closing end position, and the mold clamping position) in the mold closing step and the mold clamping step are set as a series of setting conditions. Instead of the speed and position of the crosshead 151, the speed and position of the movable platen 120 may be set. Instead of setting the position of the crosshead (for example, the mold clamping position) or the position of the movable platen, the mold clamping force may be set.

However, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits the amplified driving force to the movable platen 120. Its magnification is also referred to as the toggle magnification. The toggle magnification is changed according to an angle θ formed by the 1 st link 152 and the 2 nd link 153 (hereinafter, also referred to as "link angle θ"). The link angle θ is obtained from the position of the crosshead 151. When the link angle θ is 180 °, the toggle magnification becomes maximum.

When the thickness of the mold apparatus 10 changes due to, for example, replacement of the mold apparatus 10 or a change in temperature of the mold apparatus 10, the mold thickness is adjusted so that a predetermined clamping force is obtained at the time of clamping. In the mold thickness adjustment, for example, at the time when the movable mold 12 contacts the mold contacting the fixed mold 11, the interval L between the fixed platen 110 and the toggle seat 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle.

The mold clamping device 100 includes a mold thickness adjusting mechanism 180 for adjusting the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle seat 130. The die thickness adjusting mechanism 180 includes: a screw shaft 181 formed at the rear end of the connection rod 140; a screw nut 182 rotatably held by the toggle seat 130; and a die thickness adjusting motor 183 for rotating a screw nut 182 screwed to the screw shaft 181.

The screw shaft 181 and the screw nut 182 are provided for each link 140. The rotation of the die thickness adjusting motor 183 can be transmitted to the plurality of lead screw nuts 182 via the rotation transmitting portion 185. A plurality of lead screw nuts 182 can be rotated in synchronization. Further, by changing the transmission path of the rotation transmission portion 185, it is also possible to rotate the plurality of screw nuts 182, respectively.

The rotation transmission portion 185 is formed of, for example, a gear. In this case, a driven gear is formed on the outer periphery of each screw nut 182, and a drive gear and an intermediate gear engaged with the plurality of driven gears and the drive gear are attached to the output shaft of the die thickness adjusting motor 183 and rotatably held at the center of the toggle seat 130. In addition, the rotation transmitting portion 185 may be formed of a belt, a pulley, or the like instead of the gear.

The operation of the die thickness adjusting mechanism 180 is controlled by the control device 700. The controller 700 drives the die thickness adjustment motor 183 to rotate the screw nut 182, thereby adjusting the position of the fixed platen 110 relative to the toggle base 130 that rotatably holds the screw nut 182, and adjusting the interval L between the fixed platen 110 and the toggle base 130.

In the present embodiment, the screw nut 182 is rotatably held with respect to the toggle base 130, and the connecting rod 140 on which the screw shaft 181 is formed is fixed to the fixed platen 110.

For example, the screw nut 182 may be rotatably held by the fixed platen 110, and the connection rod 140 may be fixed to the toggle seat 130. In this case, the interval L can be adjusted by rotating the screw nut 182.

The screw nut 182 may be fixed to the toggle base 130, and the connecting rod 140 may be rotatably held to the fixed platen 110. In this case, the interval L can be adjusted by rotating the connecting rod 140.

The screw nut 182 may be fixed to the fixed platen 110, and the connecting rod 140 may be rotatably held to the toggle seat 130. In this case, the interval L can be adjusted by rotating the connecting rod 140.

The spacing L is detected using a die thickness adjustment motor encoder 184. The mold thickness adjusting motor encoder 184 detects the rotation amount and the rotation direction of the mold thickness adjusting motor 183, and transmits a signal indicating the detection result to the control device 700. The detection results of the die thickness adjustment motor encoder 184 are used for monitoring and controlling the position and spacing L of the toggle seat 130.

The die thickness adjusting mechanism 180 adjusts the interval L by rotating one of a screw shaft 181 and a screw nut 182 that are screwed together. A plurality of die thickness adjusting mechanisms 180 may be used, or a plurality of die thickness adjusting motors 183 may be used.

Since the die thickness adjusting mechanism 180 of the present embodiment adjusts the interval L, it includes the screw shaft 181 formed in the tie bar 140 and the screw nut 182 screwed to the screw shaft 181, but the present invention is not limited thereto.

For example, the die thickness adjusting mechanism 180 may have a connecting rod temperature adjuster that adjusts the temperature of the connecting rod 140. The link temperature adjuster is installed at each link 140 and cooperatively adjusts the temperature of the plurality of links 140. The higher the temperature of the connection rod 140, the longer the connection rod 140 becomes due to thermal expansion, and the larger the interval L becomes. The temperature of the plurality of connecting rods 140 can also be independently adjusted.

The connecting rod temperature adjuster includes, for example, a heater device such as a heater, and adjusts the temperature of the connecting rod 140 by heating. The connecting rod temperature regulator may include a cooler such as a water jacket, and adjusts the temperature of the connecting rod 140 by cooling. The connecting rod temperature regulator may also include both a heater and a cooler.

The mold clamping apparatus 100 of the present embodiment is a horizontal type in which the mold opening and closing direction is the horizontal direction, but may be a vertical type in which the mold opening and closing direction is the vertical direction. The vertical mold closing device has a lower platen, an upper platen, a toggle seat, a connecting rod, a toggle mechanism, a mold closing motor, and the like. Either one of the lower platen and the upper platen may be used as a fixed platen, and the remaining one may be used as a movable platen. The lower pressing plate is provided with a lower die, and the upper pressing plate is provided with an upper die. The lower die and the upper die form a die device. The lower mold may be mounted to the lower platen via a turntable. The toggle seat is arranged below the lower pressure plate and is connected with the upper pressure plate through a connecting rod. The connecting rod connects the upper pressure plate and the toggle seat with a gap in the mold opening and closing direction. The toggle mechanism is arranged between the toggle seat and the lower pressing plate and lifts the movable pressing plate. The mold clamping motor operates the toggle mechanism. When the mold clamping device is vertical, the number of tie bars is usually 3. The number of the tie bars is not particularly limited.

Further, the mold clamping apparatus 100 of the present embodiment includes the mold clamping motor 160 as a driving source, but may include a hydraulic cylinder instead of the mold clamping motor 160. The mold clamping device 100 may have a linear motor for opening and closing the mold and an electromagnet for clamping the mold.

(Ejection device)

In the explanation of the ejector 200, similarly to the explanation of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (the right direction in fig. 1 and 2) is set as the front side, and the moving direction of the movable platen 120 when the mold is opened (the left direction in fig. 1 and 2) is set as the rear side.

The ejector 200 ejects the molded product from the mold apparatus 10. The ejector 200 includes an ejector motor 210, a motion conversion mechanism 220, an ejector rod 230, and the like.

The ejector motor 210 is mounted to the movable platen 120. The ejector motor 210 is directly connected to the motion conversion mechanism 220, but may be connected to the motion conversion mechanism 220 via a belt, a pulley, or the like.

The motion converting mechanism 220 converts the rotational motion of the eject motor 210 into the linear motion of the eject lever 230. The motion conversion mechanism 220 includes a screw shaft and a screw nut screwed to the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

The ejector rod 230 is freely movable forward and backward in the through hole of the movable platen 120. The tip end of the ejector rod 230 contacts the movable member 15 disposed inside the movable mold 12 so as to be movable forward and backward. The tip end portion of the ejector rod 230 may or may not be coupled to the movable member 15.

The ejection device 200 performs the ejection process under the control of the control device 700.

In the ejection process, the ejection motor 210 is driven to advance the ejector rod 230 from the standby position to the ejection position at a set speed, thereby advancing the movable member 15 and ejecting the molded product. Thereafter, the ejector motor 210 is driven to retract the ejector rod 230 at a set speed, and the movable member 15 is retracted to the original standby position. The position and speed of the ejector rod 230 are detected using, for example, the ejector motor encoder 211. The ejection motor encoder 211 detects the rotation of the ejection motor 210, and transmits a signal indicating the detection result to the control device 700.

(injection device)

In the explanation of the injection device 300, unlike the explanation of the mold clamping device 100 and the explanation of the ejector device 200, the moving direction of the screw 330 during filling (the left direction in fig. 1 and 2) is assumed to be the front side, and the moving direction of the screw 330 during metering (the right direction in fig. 1 and 2) is assumed to be the rear side.

The injection device 300 is provided on a slide 301 that is movable forward and backward with respect to the frame 900, and is movable forward and backward with respect to the mold device 10. The injection device 300 is in contact with the mold device 10, and fills the cavity space 14 in the mold device 10 with the molding material. The injection device 300 includes, for example, a cylinder 310, a nozzle 320, a screw 330, a metering motor 340, an injection motor 350, a pressure detector 360, and the like.

The cylinder 310 heats the molding material supplied from the supply port 311 to the inside. The supply port 311 is formed at the rear of the cylinder 310. A cooler 312 such as a water-cooled cylinder is provided on the outer periphery of the rear portion of the cylinder block 310. A heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of the cylinder 310 in front of the cooler 312.

The cylinder 310 is divided into a plurality of regions in the axial direction of the cylinder 310 (the left-right direction in fig. 1 and 2). A heating source 313 and a temperature detector 314 are provided in each region. The control device 700 controls the heater 313 so that the temperature detected by the temperature detector 314 becomes a set temperature for each region.

The nozzle 320 is provided at the distal end of the cylinder 310 and is pressed against the die apparatus 10. A heater 313 and a temperature detector 314 are provided on the outer periphery of the nozzle 320. The control device 700 controls the heater 313 so that the detected temperature of the nozzle 320 becomes the set temperature.

The screw 330 is rotatably and reciprocatingly disposed in the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the spiral groove of the screw 330. The molding material is gradually melted by heat from the cylinder 310 while being fed forward. The screw 330 is retracted as the liquid molding material is fed forward of the screw 330 and accumulated in the front of the cylinder 310. Thereafter, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and is filled in the mold apparatus 10.

A check ring 331 is attached to a front portion of the screw 330 to be movable forward and backward as a check valve for preventing the molding material from flowing backward from the front of the screw 330 when the screw 330 is pressed forward.

When the screw 330 is advanced, the check ring 331 is pushed rearward by the pressure of the molding material in front of the screw 330, and is retracted relative to the screw 330 to a blocking position where the flow path of the molding material is blocked (see fig. 2). This prevents backward flow of the molding material accumulated in front of the screw 330.

On the other hand, when the screw 330 is rotated, the check ring 331 is pushed forward by the pressure of the molding material fed forward along the spiral groove of the screw 330, and moves forward relative to the screw 330 to an open position (see fig. 1) where the flow path of the molding material is opened. Thereby, the molding material is sent to the front of the screw 330.

The check ring 331 may be any one of a co-rotating type rotating with the screw 330 and a non-co-rotating type not rotating with the screw 330.

The injection device 300 may further include a drive source for moving the check ring 331 forward and backward with respect to the screw 330 between the open position and the closed position.

The metering motor 340 rotates the screw 330. The driving source for rotating the screw 330 is not limited to the metering motor 340, and may be, for example, a hydraulic pump.

The injection motor 350 advances and retracts the screw 330. A motion conversion mechanism or the like that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330 is provided between the injection motor 350 and the screw 330. The motion conversion mechanism includes, for example, a screw shaft and a screw nut screwed to the screw shaft. Balls, rollers, and the like may be provided between the screw shaft and the screw nut. The driving source for advancing and retracting the screw 330 is not limited to the injection motor 350, and may be, for example, a hydraulic cylinder.

The pressure detector 360 detects the pressure transmitted between the injection motor 350 and the screw 330. The pressure detector 360 is provided in a pressure transmission path between the injection motor 350 and the screw 330, and detects a pressure applied to the pressure detector 360.

The pressure detector 360 transmits a signal indicating the detection result to the control device 700. The detection result of the pressure detector 360 is used to control and monitor the pressure that the screw 330 receives from the molding material, the back pressure against the screw 330, the pressure applied from the screw 330 to the molding material, and the like.

The injection device 300 performs a filling process, a pressure holding process, a metering process, and the like under the control of the control device 700.

In the filling step, the injection motor 350 is driven to advance the screw 330 at a predetermined speed, and the molding material in a liquid state accumulated in front of the screw 330 is filled into the cavity space 14 in the mold apparatus 10. The position and speed of the screw 330 is detected, for example, using an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350, and transmits a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, the filling process is switched to the holding pressure process (so-called V/P switching). The position where the V/P switching is performed is referred to as a V/P switching position. The set speed of the screw 330 can be changed according to the position, time, and the like of the screw 330.

In the filling step, after the position of the screw 330 reaches the set position, the screw 330 may be temporarily stopped at the set position, and then the V/P switching may be performed. Instead of stopping the screw 330, the screw 330 may be slightly advanced or slightly retracted before the V/P switching.

In the pressure retaining step, the injection motor 350 is driven to advance the screw 330 forward, so that the pressure of the molding material at the tip end portion of the screw 330 (hereinafter also referred to as "holding pressure") is held at a set pressure, and the molding material remaining in the cylinder 310 is pressed toward the mold apparatus 10. The shortage of the molding material due to cooling shrinkage in the mold device 10 can be compensated. The holding pressure is detected, for example, using a pressure detector 360. The pressure detector 360 transmits a signal indicating the detection result to the control device 700. The set value of the holding pressure may be changed according to the elapsed time from the start of the pressure holding step.

In the pressure retaining step, the molding material in the cavity space 14 in the mold apparatus 10 is gradually cooled, and the entrance of the cavity space 14 is closed by the solidified molding material at the end of the pressure retaining step. This state is called gate sealing and prevents backflow of the molding material from the cavity space 14. After the pressure holding step, the cooling step is started. In the cooling step, the molding material in the cavity space 14 is solidified. In order to shorten the molding cycle time, the metering step may be performed in the cooling step.

In the metering step, the metering motor 340 is driven to rotate the screw 330 at a predetermined rotation speed, and the molding material is fed forward along the spiral groove of the screw 330. With this, the molding material gradually melts. The screw 330 moves backward as the liquid molding material is sent to the front of the screw 330 and accumulated in the front of the cylinder 310. The rotational speed of the screw 330 is detected using, for example, a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340, and transmits a signal indicating the detection result to the control device 700.

In the metering step, the injection motor 350 may be driven to apply a predetermined back pressure to the screw 330 in order to restrict the screw 330 from rapidly moving backward. The back pressure against the screw 330 is detected, for example, using a pressure detector 360. The pressure detector 360 transmits a signal indicating the detection result to the control device 700. When the screw 330 is retracted to the metering completion position and a predetermined amount of the molding material is accumulated in front of the screw 330, the metering process is completed.

The injection device 300 of the present embodiment is of a coaxial screw type, but may be of a premolded type or the like. In the injection device of the preplasticizing method, the molding material melted in the plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. The screw is rotatably or rotatably and freely advanced and retreated in the plasticizing cylinder, and the plunger is freely advanced and retreated in the injection cylinder.

Further, the injection device 300 of the present embodiment is a horizontal type in which the axial direction of the cylinder 310 is the horizontal direction, but may be a vertical type in which the axial direction of the cylinder 310 is the vertical direction. The mold clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

(moving device)

In the explanation of the moving device 400, similarly to the explanation of the injection device 300, the moving direction of the screw 330 during filling (the left direction in fig. 1 and 2) is assumed to be the front side, and the moving direction of the screw 330 during metering (the right direction in fig. 1 and 2) is assumed to be the rear side.

The moving device 400 advances and retreats the injection device 300 with respect to the mold device 10. Then, the moving device 400 presses the nozzle 320 to the mold device 10 to generate a nozzle contact pressure. The traveling apparatus 400 includes a hydraulic pump 410, a motor 420 as a driving source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

The hydraulic pump 410 has a 1 st port 411 and a 2 nd port 412. The hydraulic pump 410 is a pump capable of rotating in both directions, and generates hydraulic pressure by switching the rotation direction of the motor 420 to absorb hydraulic fluid (for example, oil) from one of the 1 st port 411 and the 2 nd port 412 and discharge the hydraulic fluid from the other. The hydraulic pump 410 can also absorb the hydraulic fluid from the tank and discharge the hydraulic fluid from either the 1 st port 411 or the 2 nd port 412.

The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 by a rotation direction and a rotation torque according to a control signal from the control device 700. The motor 420 may be an electric motor or an electric servomotor.

The cylinder 430 includes a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed with respect to the injection device 300. The piston 432 divides the interior of the cylinder body 431 into a front chamber 435 as a 1 st chamber and a rear chamber 436 as a 2 nd chamber. The piston rod 433 is fixed with respect to the fixed platen 110.

The front chamber 435 of the hydraulic cylinder 430 is connected to the 1 st port 411 of the hydraulic pump 410 via the 1 st flow path 401. The working fluid discharged from the 1 st port 411 is supplied to the front chamber 435 through the 1 st flow path 401, and the injection device 300 is pushed forward. The injection device 300 advances and the nozzle 320 is pressed by the stationary mold 11. The front chamber 435 functions as a pressure chamber that is generated by the pressure of the hydraulic fluid supplied from the hydraulic pump 410 and the nozzle contact pressure of the nozzle 320.

On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the 2 nd port 412 of the hydraulic pump 410 via the 2 nd flow path 402. The hydraulic fluid discharged from the 2 nd port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 through the 2 nd flow path 402, whereby the injection device 300 is pushed rearward. The injection device 300 is retreated and the injection nozzle 320 is separated from the stationary mold 11.

In the present embodiment, the moving device 400 includes the hydraulic cylinder 430, but the present invention is not limited thereto. For example, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into the linear motion of the injection device 300 may be used instead of the hydraulic cylinder 430.

(control device)

As shown in fig. 1 to 2, the control device 700 includes a CPU (Central processing unit)701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by causing the CPU701 to execute a program stored in the storage medium 702. The control device 700 receives a signal from the outside through the input interface 703 and transmits a signal to the outside through the output interface 704.

The control device 700 repeats the mold closing step, the mold opening step, and the like, to repeatedly manufacture a molded product. During the mold closing step, the control device 700 performs a metering step, a filling step, a pressure maintaining step, and the like. A series of operations for obtaining a molded product, for example, operations from the start of a metering step to the start of the next metering step, are also referred to as "injection" or "molding cycle". Also, the time required for 1 injection is also referred to as "molding cycle time".

The control device 700 is connected to the operation device 750 or the display device 760. Operation device 750 receives an input operation by a user, and outputs a signal corresponding to the input operation to control device 700. Display device 760 displays an operation screen corresponding to an input operation in operation device 750, under the control of control device 700.

The operation screen is used for setting the injection molding machine. A plurality of operation screens are prepared, or switched to be displayed, or overlapped to be displayed. The user operates the operation device 750 while viewing the operation screen displayed on the display device 760 to perform setting (including input of set values) of the injection molding machine.

The operation device 750 and the display device 760 may be formed of, for example, a touch panel and integrated. Further, although the operation device 750 and the display device 760 of the present embodiment are integrated, they may be provided separately. Also, a plurality of operating devices 750 may be provided.

(movement control based on deformation of frame)

Fig. 3 is a diagram showing a mold clamping device and a frame according to an embodiment. The frame 900 has, for example, an upper frame-shaped portion 901, and is provided with the mold clamping device 100; a lower frame portion 902 to which a horizontal pad installed on the floor of a factory or the like is attached; and a pillar 903 provided between the upper frame portion 901 and the lower frame portion 902. The horizontal pads are attached to a plurality of portions of the lower frame 902 by adjusting the height from the ground to the lower frame 902.

The upper frame-shaped portion 901 is formed by joining a plurality of beam portions by welding or the like, and is formed into, for example, a rectangular frame shape when viewed in the vertical direction. Similarly, the lower frame portion 902 is formed by joining a plurality of beam portions by welding or the like, and is formed into, for example, a rectangular frame shape when viewed in the vertical direction. The column portion 903 extends in the vertical direction, and a plurality of columns are provided between the upper frame-shaped portion 901 and the lower frame-shaped portion 902.

Frame 900 has a welded portion for joining a plurality of components constituting frame 900 by welding. For example, the frame 900 has a welded portion 904 joining the upper end of the pillar portion 903 and the upper frame-shaped portion 901, and a welded portion 905 joining the lower end of the pillar portion 903 and the lower frame-shaped portion 902. The frame 900 has a welded portion for joining the plurality of beam portions constituting the upper frame-shaped portion 901 and a welded portion for joining the plurality of beam portions constituting the lower frame-shaped portion 902.

The frame 900 supports the movable platen 120. The movable platen 120 is advanced and retreated with respect to the frame 900, thereby advancing and retreating the movable mold 12. When the movable platen 120 and the movable mold 12 are moved, the frame 900 receives a reaction force from the movable platen 120 and deforms.

On the frame 900, a frame deformation detector 906 that detects deformation of the frame 900 is provided. The frame deformation detector 906 is constituted by a strain gauge or the like. The frame deformation detector 906 transmits a signal indicating the detection result to the control device 700.

Frame deformation detector 906 may detect deformation of a welded portion (welded portion 904 in fig. 3) of frame 900. This is because the welded portion is a bent portion of the frame 900, and therefore the reaction force from the movable platen 120 is easily concentrated. The reason is that the welded portion is more likely to be broken than the pillar portion 903 and the beam portion by the influence of heat during welding.

Preferably, the frame deformation detector 906 is capable of detecting deformation of the welded portions (for example, the welded portions 904 and 905) joining the components of the frame 900 in the direction (for example, the Z direction) orthogonal to the moving direction (in fig. 3, the X direction) of the movable platen 120. This is because when the movable platen 120 and the movable mold 12 are moved, the shear stress acts on the welded portion by the reaction force from the movable platen 120.

When the frame deformation detector 906 detects the deformation of the welded portion, it may be provided so as not to be exposed from the welded portion, or may be provided so as to straddle the welded portion. For example, as shown in fig. 3, the frame deformation detector 906 may be provided so as to be accommodated in the welding portion 904, or may be provided on the upper frame-shaped portion 901 and the column portion 903 across the welding portion 904.

Fig. 4 is a diagram showing constituent elements of a control device according to an embodiment as functional blocks. Each functional block illustrated in fig. 4 is a conceptual diagram, and is not necessarily required to be physically configured as illustrated in the drawings. All or part of each functional block can be functionally or physically distributed/integrated in an arbitrary unit. All or any part of the processing functions performed in the functional blocks may be realized by a program executed by a CPU or realized as hardware based on wired logic.

The control device 700 includes, for example, a movement control unit 711 that controls movement of the movable platen 120 with respect to the frame 900 by controlling movement of the crosshead 151 with respect to the frame 900.

The movement control unit 711 controls the mold clamping motor 160 so that the movement speed of the crosshead 151 becomes a set speed. The movement controller 711 includes a control command calculation unit 712 (see fig. 5 and 6) that generates a control command based on the set speed Vref and the actual speed V, a drive unit 713 (see fig. 5 and 6) that supplies an ac current to the mold clamping motor 160 in accordance with the control command, and the like.

The control command calculation unit 712 generates a control command based on the set speed Vref and the actual speed V. For example, the control command calculation unit 712 generates an output wave of the driving unit 713 such that the deviation between the set speed Vref and the actual speed V becomes zero. For example, PI calculation, pid calculation, or the like can be used to generate the output wave of the driver 713. The control command calculation unit 712 compares the output wave of the driving unit 713 with the transmission wave to generate a PWM (Pulse Width Modulation) signal.

The driving unit 713 is configured by an inverter or the like that converts dc power into ac power. The inverter has, for example, a plurality of legs each including 2 switching elements. Diodes are connected in anti-parallel to the switching elements. Diodes may be built into each switching element. The inverter converts the PWM signal from the control command calculation unit 712 and supplies ac power to the mold clamping motor 160. The control method of the driver 713 is not limited to PWM.

As shown in fig. 4, the control device 700 includes a frame deformation evaluation unit 715 that performs at least one of measurement and estimation of the deformation of the frame 900 based on the movement of the movable platen 120. By performing at least one of measurement and estimation of the deformation of frame 900, it is possible to investigate the cause and measure of the deformation of frame 900 and to suppress damage to frame 900.

The frame deformation evaluation unit 715 measures the deformation of the frame 900 by using, for example, the frame deformation detector 906 provided in the frame 900. By using the frame deformation detector 906, the deformation of a specific portion of the frame 900 can be correctly detected. Further, by using a plurality of frame deformation detectors 906, the distribution of the deformation of the frame 900 can also be measured. When the deformation of one portion is larger than that of the other portion, it can be determined that the stress is concentrated in the portion having the larger deformation.

The deformation of the frame 900 is generated by the reaction force RF from the movable platen 120 and is proportional to the reaction force RF. Therefore, the deformation of the frame 900 can be obtained by multiplying the reaction force RF from the movable platen 120 by a predetermined coefficient C. The coefficient C can be obtained in advance by stress analysis using a finite element method or the like.

The reaction force RF from the movable platen 120 can be represented by, for example, the product (a × W) of the acceleration a of the movable platen 120 and the total weight W of the movable platen 120 and the movable mold 12. Therefore, the frame deformation evaluation unit 715 can estimate the deformation of the frame 900 from the acceleration a of the movable platen 120. The deformation of the frame 900 is calculated using the formula a × W × C.

Here, the acceleration a of the movable platen 120 is obtained by detecting the position of the crosshead 151 using, for example, the clamp motor encoder 161 and converting the position of the crosshead 151 into the position of the movable platen 120. The position of the crosshead 151 corresponds to the position of the movable platen 120 in a one-to-one manner. Data indicating the correspondence relationship is stored in advance in the storage medium 702 and read as needed.

The data stored in the storage medium 702 in advance is read and used for the total weight W of the movable platen 120 and the movable mold 12.

The reaction force RF from the movable platen 120 can also be represented by the product (T × SL × TM) of the magnitude T of the torque of the mold clamping motor 160 that moves the movable platen 120 and the lead SL of the ball screw as the motion conversion mechanism 170 and the toggle magnification TM. Therefore, the frame deformation evaluation unit 715 may estimate the deformation of the frame 900 based on the magnitude of the torque of the mold clamping motor 160 that moves the movable platen 120. The deformation of the frame 900 is calculated using the formula T × S L × TM × C.

Here, the lead SL of the ball screw is, for example, a moving distance in which the screw shaft 171 rotates and the screw nut 172 moves in the axial direction, and the screw nut 172 advances in the axial direction by one rotation of the screw shaft 171. The screw shaft 171 may be moved in the axial direction by rotation of the screw nut 172, or the screw nut 172 may be fixed and the screw shaft 171 may be moved in the axial direction while rotating. The lead SL of the ball screw is used by reading data stored in advance in the storage medium 702.

Then, for example, the toggle magnification TM is obtained by detecting the position of the cross head 151 using the clamp motor encoder 161 and converting the position of the cross head 151 into the toggle magnification TM. The more forward the position of the crosshead 151 is, the closer the link angle θ is to 180 ° and the larger the toggle magnification TM becomes. The data stored in advance in the storage medium 702 is read and used for the correspondence among the position of the crosshead 151, the link angle θ, and the toggle magnification TM.

The magnitude T of the torque of the clamp motor 160 can be detected by a clamp motor torque detector 162. The mold clamping motor torque detector 162 detects the torque of the mold clamping motor 160 by detecting the value of the current supplied to the mold clamping motor 160, for example. The magnitude T of the torque of the mold clamping motor 160 can be obtained from a control command value for the driving unit 713.

As shown in fig. 4, the control device 700 may include a movement correction unit 716 that corrects the movement of the movable platen 120 by the movement control unit 711 based on the deformation of the frame 900 obtained by the frame deformation evaluation unit 715. The movement correction unit 716 corrects the movement of the movable platen 120 by the movement control unit 711 so that the deformation of the frame 900 obtained by the frame deformation evaluation unit 715 becomes equal to or less than a reference value. The relationship between the magnitude of deformation of the frame 900 and the deterioration rate of the frame 900 is obtained in advance through a test, and a reference value of deformation of the frame 900 is set based on the test result. The movement control unit 711 corrects the movement of the movable platen 120 in accordance with the correction by the movement correction unit 716. This can suppress deformation of the frame 900 and damage to the frame 900.

Fig. 5 is a diagram showing a control device for limiting the magnitude of torque by the movement correction unit according to an embodiment. The movement correction unit 716 shown in fig. 5 limits the torque of the mold clamping motor 160 so that the deformation of the frame 900 obtained by the frame deformation evaluation unit 715 becomes equal to or less than a reference value. The movement correction unit 716 limits the supply current of the mold clamping motor 160 and limits the magnitude of the torque of the mold clamping motor 160, for example, by the control command of the correction control command calculation unit 712. This can suppress deformation of the frame 900 and damage to the frame 900.

Fig. 6 is a diagram showing a control device for correcting a velocity pattern by the movement correction unit according to an embodiment. The movement correction unit 716 shown in fig. 6 corrects the movement speed pattern of the crosshead 151 so that the deformation of the frame 900 obtained by the frame deformation evaluation unit 715 becomes equal to or less than a reference value. The movement correction unit 716 calculates a correction amount of the set speed Vref based on the deformation of the frame 900 and the set speed Vref, and corrects the movement speed pattern of the crosshead 151 by correcting a deviation between the set speed Vref and the actual speed V. This can suppress deformation of the frame 900 and damage to the frame 900.

Fig. 7 is a diagram showing a speed pattern of the crosshead before correction, deformation of the frame before correction, a speed pattern of the crosshead after correction, and deformation of the frame after correction in the mold closing process and the mold clamping process according to the embodiment. Fig. 7(a) is a diagram showing a speed pattern of the crosshead before correction in the mold closing step and the mold clamping step according to the embodiment. Fig. 7(b) is a diagram showing deformation of the frame before correction in the mold closing step and the mold clamping step according to the embodiment. Fig. 7(c) is a diagram showing a corrected speed pattern of the crosshead in the mold closing step and the mold clamping step according to the embodiment. Fig. 7(d) is a diagram showing the deformation of the frame after correction in the mold closing step and the mold clamping step according to the embodiment.

The movement control unit 711 controls the mold clamping motor 160 so that the movement speed of the crosshead 151 becomes a set speed. In the mold closing step, the moving speed of the crosshead 151 is accelerated from zero to a set speed set by the user, and after the moving speed is maintained at the set speed, the moving speed is decelerated from the set speed to substantially zero. Next, in the mold clamping process, the moving speed of the crosshead 151 is accelerated and then decelerated. The acceleration and deceleration of the crosshead 151 are used by reading data that is set in advance and stored in the storage medium 702. The acceleration and deceleration of the crosshead 151 may be set by the manufacturer of the injection molding machine.

The frame deformation evaluation unit 715 obtains a temporal change in deformation of the frame 900 in the mold closing step and the mold clamping step, and checks whether the deformation of the frame 900 exceeds a reference value. When the deformation of the frame 900 exceeds the reference value, the frame deformation evaluation unit 715 determines a period during which the deformation of the frame 900 exceeds the reference value.

For example, in fig. 7, the period in which the deformation of the frame 900 exceeds the reference value is the following periods (1) to (3). During the period (1) (the period from the time t1 to the time t 2), the moving speed of the crosshead 151 is accelerated from V1 to V2. During the period (2) (the period from the time t3 to the time t 4), the moving speed of the crosshead 151 is decelerated from V3 to V4. During the period (3) (the period from the time t5 to the time t 6), the moving speed of the crosshead 151 is accelerated from V5 to V6.

The movement correcting unit 716 corrects the movement speed pattern of the crosshead 151 so that the deformation of the frame 900 becomes equal to or less than a reference value. Specifically, during a period in which the deformation of the frame 900 exceeds the reference value (for example, during the periods (1) to (3) described above), the magnitude of the acceleration or the magnitude of the deceleration is reduced, and the reaction force from the movable platen 120 is suppressed.

The movement correcting unit 716 may reduce the magnitude of the acceleration and the magnitude of the deceleration not only in a period in which the deformation of the frame 900 exceeds the reference value but also in a period adjacent to a period in which the deformation of the frame 900 exceeds the reference value.

The movement control unit 711 controls the movement of the movable platen 120 in accordance with the velocity pattern (for example, the velocity pattern shown in fig. 7 c) corrected by the movement correction unit 716 in the next and subsequent injections. As a result, as shown in fig. 7(d), deformation of the frame 900 can be suppressed to a reference value or less, and damage to the frame 900 can be suppressed.

Further, the following process may be repeated until the deformation of the frame 900 becomes a reference value or less: the temporal change in the deformation of the frame 900 is obtained by the frame deformation evaluation unit 715, and the movement speed pattern of the crosshead 151 is corrected by the movement correction unit 716.

In fig. 7, the correction of the moving speed pattern of the crosshead 151 in the mold closing step and the mold closing step is described, but the moving speed pattern of the crosshead 151 in the mold opening step may be corrected similarly.

The movable platen 120 corresponds to a movable member described in claims, and the mold clamping motor 160 corresponds to a motor described in claims. The movable member is not limited to the movable platen 120. For example, the movable member may be the toggle seat 130, in which case the motor is a die thickness adjustment motor 183. Also, the movable component may be the injection device 300, in which case the motor is the motor 420 of the movement device 400.

(modification and improvement)

While the embodiments of the injection molding machine and the like have been described above, the present invention is not limited to the above embodiments and the like, and various modifications and improvements can be made within the spirit of the present invention described in the claims.

The control device 700 may further include a mode selection unit that selects whether or not to perform correction of the movement of the movable member based on the deformation of the frame 900, based on an operation signal from the operation device 750, the operation device 750 transmitting an operation signal corresponding to an input operation by a user to the control device 700. The convenience of the user can be improved.

The control device 700 may include a deterioration degree detection unit that detects a deterioration degree of the frame 900 from the deformation of the frame 900 obtained by the frame deformation evaluation unit 715. As the deterioration of the frame 900 progresses, the deformation of the frame 900 due to the movement of the movable member increases. Therefore, the degree of deterioration of the frame 900 can be estimated from the magnitude of deformation of the frame 900.

The control device 700 may include a mechanical life estimating unit that estimates the mechanical life of the frame 900 from the deformation of the frame 900 obtained by the frame deformation evaluating unit 715. The mechanical life estimating unit estimates the mechanical life based on the degree of degradation detected by the degradation degree detecting unit. The following can be inferred: the greater the degree of degradation detected by the degradation degree detection unit, that is, the more the degradation of the frame 900 progresses, the shorter the life of the frame 900.

The control device 700 may include an alarm generating unit that generates an alarm based on the deformation of the frame 900 determined by the frame deformation evaluating unit 715. For example, the alarm issuing unit issues an alarm when the deformation of the frame 900 calculated by the frame deformation evaluating unit 715 is out of the allowable range. The alarm issuing unit may issue an alarm based on the degree of degradation determined by the degradation degree detecting unit, the mechanical life determined by the mechanical life estimating unit, or the like. The user can be alerted by the issuance of an alarm and prompted to repair the frame 900. Various kinds of alarms can be prepared. The alarm is generated by an image, a sound, or the like, and the display device 760, a warning lamp, a buzzer, or the like can be used as the generating device.

Claims

1. An injection molding machine, comprising:

a frame;

a movable member supported by the frame;

2. The injection molding machine of claim 1, having:

and a movement correction unit that corrects the movement of the movable member by the movement control unit, based on the deformation obtained by the frame deformation evaluation unit.

3. The injection molding machine according to claim 2,

the movement correction unit corrects the movement of the movable member based on the movement control unit so that the deformation obtained by the frame deformation evaluation unit is equal to or less than a reference value.

4. The injection molding machine according to any one of claims 1 to 3,

the frame deformation evaluation unit measures the deformation of the frame using a deformation detector provided to the frame.

5. The injection molding machine according to any one of claims 1 to 3,

the frame deformation evaluation unit estimates the deformation of the frame from an acceleration of the movable member.

6. The injection molding machine according to any one of claims 1 to 3,

the frame deformation evaluation unit estimates the deformation of the frame based on a torque of a motor that moves the movable member.